Question: Simplify the following expression: $t = \dfrac{9}{4k} + \dfrac{1}{7k}$
In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $4k$ and $7k$ $\lcm(4k, 7k) = 28k$ $ t = \dfrac{7}{7} \cdot \dfrac{9}{4k} + \dfrac{4}{4} \cdot \dfrac{1}{7k} $ $t = \dfrac{63}{28k} + \dfrac{4}{28k}$ $t = \dfrac{63 +4}{28k}$ $t = \dfrac{67}{28k}$